join to c language session 2 by reza gholamzadeh - 1387 1st semester

Join to C languageJoin to C languageSession 2

By Reza Gholamzadeh - 1387 1st Semester

We have an overview to:We have an overview to: Anatomy of a C program What is a function? Declaration of variables

◦ Data types◦ Choose correct names◦ Initialize

Assignment Blocks Comments Input and output functions Conditional statements

◦ if◦ switch

Loops◦ while◦ do – while◦ for


Anatomy of a C Anatomy of a C programprogram


Preprocess instructions

Typical C program

Prototypes

Global variables

main() function

function A()

function B()

statements

statements

statements

Declarations

Assignment

Function

Control

null

What is a function?What is a function?A function is a self-contained unit of

program code designed to accomplish a particular task

a function can both produce actions (such as procedures) and provide values

they save you from repetitious programming

it makes a program more modular, hence easier to read and easier to change or fix


Declaration of variablesDeclaration of variables Declaration structure:DataType Var1Name = [initialization],[Vare2Name] = [initialization],…;

For example:

int sum = 2;

float avg = 0, var = 1.0;

char mark = ‘A’;

Available data types:int , char , float , double , long , short , ...

Available names for variables:1. The characters at your disposal are lowercase letters, uppercase letters,

digits, and the underscore (_)

2. The first character must be a letter or an underscore

For example:

firstName , _sumOf , taxi1 , ...


AssignmentAssignmentBy value

Example:

X = 12;

sum = 1298.998;

ch = ‘q’;

By expressionsExample:

avg = ( a + b + c ) / 3;

x = sin(y);

var1 = var2;


BlocksBlocksA block starts with ‘{‘ and ends with

‘}’Variables defined in a block , can`t

be used outside of the blockEach function have a blockBlocks used for grouping statementsBlocks can be used in blocksA block:{

statement1;statement2;…

}


CommentsCommentsThe parts of the program enclosed in the /*

*/ symbols are comments

Using comments makes it easier for someone (including yourself) to understand your program

they can be placed anywhere

Everything between the opening /* and the closing */ is ignored by the compiler

use the symbols // to create comments that are confined to a single line


Input and output functionsInput and output functionsOutput function printf()Examples:

printf(“Hello C language!”);

printf(“My name is:\nReza Gholamzadeh”);

printf(“your code is %d”,code);

printf(“\t a + b = %f”,a+b);

Input function scanf()Examples:

scanf(“%d”,&input);

scanf(“%f%f%f”,&number1,&number2,&number3);

scanf(“(%d,%d)”,&pointX,&pointY);


Conditional statementsConditional statementsif statement structures


if (condition) statement;

if (condition){ statement1; ...}

if (condition) statement1;else statement2;

if (condition){ statement1; ...}else { statement1; ...}

if (condition1){ statement1; ...}else if(condition2){ statement1; ...}else if(condition3){ statement1; ...}...else{ statement1; ...}

Conditional statementsConditional statementsswitch statement structure


switch (variable){ case value1:

statement1;...break;

case value2:statement1;...break;

case value3:statement1;...break;

.

.

.

[default:]statement1;...

}

LoopsLoopswhile loop structures

do – while loop structures


while (condition) statement;

while (condition){ statement1; statement2; ...}

do statement;while (condition);

do{ statement1; statement2; ...}while (condition);

LoopsLoopsfor loop structures


for (initializeCounter; condition; step){ statement1; statement2; ...}

for (initializeCounter; condition; step) statement;

Now Now ready to write some ready to write some

programsprograms


Example 1Example 1

A program which gets n number and calculates the average.


Output:

Enter value of n: 5Enter number 1: 6Enter number 2: 7Enter number 3: -1Enter number 4: 16Enter number 5: -3

Average is: 5.00

Example 1Example 1


#include <stdio.h>

int main()

{

int n,input,sum = 0,i;

float avg = 0.0;

for(i=0; i<n; i++)

{

printf(“enter number %d: “,i+1);

scanf(“%d”,&input);

sum+=input;

}

avg = sum/n;

printf(“average is %.2f”,avg);

return 0;

}

Example 2Example 2

A program which gets natural numbers of n and r and calculates the c(n,r).This should include a function to calculate the factorial.


Output:

Enter n and r in format (n,r): (5,3)

Result of c(5,3) is: 10

Example 2Example 2


#include <stdio.h>

int fact(int);

int main()

{

int r,n;

float c;

printf(“enter n and c in (c,r) format: “);

scanf(“(%d,%d)”,&n,&r);

if(n<r)

{

printf(“incorrect values.”);

return 1;

}

c = fact(n)/(fact(r)*fact(n-r));

printf(“Result of c(%d,%d) is: %f“,n,r,c);

return 0;

}

Example 2Example 2


int fact(int input)

{

int output = 1 , i;

if(input == 0)

return 1;

for(i = input; i>=1; i--)

output *= i;

return output;

}

Example 3Example 3

A program which gets float point numbers and calculates the minimum & maximum of them.


Output:

Enter value of n: 3Enter number 1: -1Enter number 2: 2.5Enter number 3: 2

Max is 2.50 and min is -1.00

Example 3Example 3


#include <stdio.h>int main(){ int n,i; float input,Min,Max; printf(“Enter value of n: “);

scanf(“%d”,&n); if(n == 0)

return 1; printf(“Enter number 1: “); scanf(“%f”,&input); Max = input; Min = input; for(i = 2; i<=n; i++) {

printf(“Enter number 1: “);scanf(“%f”,&input);

if(input < Min)Min = input;

else if(input > Max)Max = input;

}printf(“\nMax is &f and Min is %f”,Max,Min);

return 0;

}

Example 4Example 4

A program which gets three numbers and shows us that numbers can be the lengths of a triangle or not.


Output:

Enter a,b,c in {a,b,c} format: {2,4,3}

Yes.

Example 4Example 4


#include <stdio.h>

int main()

{

int a,b,c;

printf(“enter a,b,c in {a,b,c} format: “);

scanf(“{%d,%d,%d}”,&a,&b,&c);

if(a+b>c && a+c>b && b+c>a)

printf(“\nYes.”);

else

printf(“\nNo.”);

return 0;

}

Example 5Example 5

A program which gets the coordinatios of vector A & B, and calculate the A*B.


Output:

Enter A in (a,b,c) format: (2,2,3)Enter A in (d,e,f) format: (1,4,-2)

A*b is: (-16,7,6)

Example 5Example 5


#include <stdio.h>

int main()

{

int a,b,c,d,e,f;

printf(“enter A in (a,b,c) format: “);

scanf(“(%d,%d,%d)”,&a,&b,&c);

printf(“enter B in (d,e,f) format: “);

scanf(“(%d,%d,%d)”,&d,&e,&f);

printf(“\nA*B is: (%d,%d,%d)”,(b*f-c*e),(c*d-a*f),(a*e-b*d));

return 0;

}

Exercise 1Exercise 1 A program which gets 4

numbers and shows the maximum and minimum of them . This program should include two functions for calculation of maximum and minimum of two numbers.


Output:

Enter numbers: -1 , 12.05 , 11 , 0

Minimum is -4.00 and maximum is 12.05)

Exercise 2Exercise 2 A program which gets a special

character and a number (n).It will get other inputs(in character mode) until the nth character of that special character is inputted.


Output:

Enter your character: CEnter number of repeating: 21.Enter character: D2.Enter character: C3.Enter character: A4.Enter character: 55.Enter character: C

Program finished after 5 inputs.

Exercise 3Exercise 3A program which gets 2 numbers

and will show all the prime numbers between these two number .The program should include a function to calculate the prime number.


Output:

Enter A and B: 25 4

Result is: 5,7,11,13,17,19,23I find 7 prime number between 4 and 25.

Exercise 4Exercise 4A program which reads a number

in binary base and converts it into decimal base.


Output:

Enter your binary number: 10011

Your number in decimal: 19

NotesNotes1. Codes must be executable2. Use less variables as you can (the

less memory)3. Codes should be readable (similar

to example’s codes)4. Codes should give the right answer

(by having bugs, it gets point by the amount of errors)

5. Must be mailed in the time given( Till 1:00 PM of next Saturday)


join to c language session 2 by reza gholamzadeh - 1387 1st semester

Documents

semester slide

condition statement1

statement1 statement2

semester switch variable

statements blocks

block blocks

input scanf

printfhello c language